Configuring HP-UX For Peripherals

Chapter 2 53
Managing PCI Cards with OLAR
Performing OLAR procedures from the command line
Dynamically Loadable Kernel Modules (DLKM)
DLKM provides the ability to auto load software drivers. When a
DLKM-based driver is installed on a system, that driver is registered
with, and configured into the system (kernel). The driver can be force
loaded, demand loaded, or auto loaded.
• In the first case, the behavior is similar to static drivers in that the
driver is always loaded into the kernel upon system boot.
• In the second case, the driver is loaded by executing a utility in user
space.
• When the device is opened by any application, the driver is
automatically loaded and linked into the kernel, unbeknownst to the
user or the application (if not already loaded and linked into the
kernel). If the driver is in core, but is not being used at a given time, it
can be unloaded from core memory, thus freeing that memory. This
also can happen without user or application impact.
When performing OLAR procedures, DLKM drivers often provide
significant advantages over traditional device drivers.
As an example, when on-line adding a new interface card, your
procedure may look something like the following:
1. Power down the slot
2. Insert new interface card
3. Power up the slot
4. Run ioscan - no drivers claim card
5. Run rad -c to obtain device information
6. Match this information with that contained in the driver database
7. Auto-load the correct DLKM driver
8. Run ioscan again to have the driver claim the card
This process can be performed without rebuilding the kernel and
rebooting the system.